1. Field of the Invention
The present invention relates to an image data processing apparatus to which a television (TV) camera is connected and, more particularly, to an image data processing apparatus for converting image data from a TV camera into a digital signal and processing it.
2. Related Background Art
In recent years, in association with the rapid development of image data processing apparatuses including mainly electronic computers, there has been developed the image data processing apparatus in which images drawn on documents are read out by an image inputting apparatus such as an image reading apparatus or the like. The readout image data is processed by an arithmetic operation processing apparatus, the processed image data is sent to an output apparatus such as a laser beam printer or the like, and thereby the recording image is obtained. However, to input a stereoscopic image such as scenery or the like to the image data processing apparatus and record it, the scenery must be photographed by a camera as a still photograph. Then, the developed still photograph must be read and input by the image input apparatus such as an image reading apparatus or the like, so that many troublesome operations are necessary. On the other hand, a general image data processing apparatus such that the stereoscopic image photographed by the TV camera apparatus can be directly output as the recording image is not put into practical use yet.
In the conventional image data processing apparatus, a density pattern method, a dither method, or the like is used as the method of expressing a half-tone image such as a photograph or the like as a binary digital signal. However, if the density of pixel data is converted by use of a fixed pattern, a moire is produced for every pixel matrix which was referred. Further, there is also the drawback such that if a random pattern is used, the noise increases and the quality of the reproduced image deteriorates.
Moreover, according to the density pattern method and dither method, even if the resolution of the output apparatus changes, the converting method is always constant. Therefore, if such a converting method is used in combination with the output apparatus having a high resolution, the data needs to be thinned out when the data is supplied to the output apparatus having a low resolution, so that the picture quality deteriorates because of the thin-out process of the data. There is also the drawback such that, on the contrary, if the resolution is set in accordance with the output apparatus having a low resolution, the high picture quality cannot be derived from the output apparatus having a high resolution.